Low-pressure system for producing normal aldehydes by hydroformylation of .alpha.-olefins

Versatile Phosphite Ligands Based on Silsesquioxane Backbones

“…[17] Phosphites are generally better p-acceptors than phosphines and therefore have great potential in hydroformylation. The metal-CO bond is weakened, leading to accelerated CO dissociation and hence higher reaction rates compared to phosphines.…”

Synthesis of 3‐Substituted Furans by Hydroformylation

“…Pruett and Smith reported that phosphites are more effective than phosphines for the hydroformylation of allylic alcohols. [19] However, the use of triphenyl phosphite [P(OPh) 3 ] in our system did not afford the hydroformylated product (entry 4). From these experiments, we concluded that PPh 3 was the ligand of choice for our catalytic system (entry 1).…”

Carbon Monoxide as a Chemical Feedstock: Carbonylation Catalysis

“…In the last decade this has been demonstrated for a large number of substrates under mild conditions by Garland and coworkers [23]. The key factor diminishing the overall effectiveness of these catalysts (apart from selectivity) is the position of the equilibrium between HRh(CO) 4 and Rh 4 (CO) 12 and/or Rh 6 (CO) 16 , which is strongly in favor of the latter clusters, thus diminishing the initial rate of reaction. Since the resting state under mild conditions is the rhodium-acyl species, potentially all rhodium participates in the catalytic cycle, and depending on the rates of equilibration between the carbonyl complexes and the competing rate of insertion of alkene, there may be no rhodium residing in the Rh 4 (CO) 12 sink.…”

“…It showed unprecedented selectivity towards the linear aldehyde at satisfactory rates; l/b = 50 and more recently values as high as 300 were reported [56]! In later studies Casey and Whiteker proved that key to this invention was the bis-equatorial mode of coordination of the diphosphine in trigonal bipyramid (D e-e in Scheme 9.1) complexes (15)(16)(17)(18). In the early 1990s, Casey and coworkers [57] and Yamamoto [58] designed several other ligands that might prefer wider bite angles, e.g.…”

“…Phosphites, first used by Pruett and Smith [16], came into focus again after the peculiar behavior of bulky phosphites was reported by van Leeuwen [17]. In particular, diphosphites have been addressed by many authors after their favorable effect on rate and selectivity for many substrates had been discovered by Bryant and coworkers [18].…”